The present invention is directed to facilitating air flow through the nasal passages of an animal. Specifically, the invention provides nasal support devices and methods for supporting soft tissue structures of the nasal passages of an animal.
Portions of the following discussion of the nasal anatomy of domestic animals are excerpted from R. Nickel et al., The Viscera of Domestic Mammals, (2nd revised ed.), Springer-Verlag, New York, Hiedelberg, Berlin (1979), pp. 211-221. This is an excellent text on the comparative visceral anatomy of domestic mammals. As used herein, the terms xe2x80x9cmammalxe2x80x9d and xe2x80x9canimalxe2x80x9d are used synonymously and refer to non-human mammals.
The nasal anatomy of animals is considerably different than that of a human. Unlike the human nose that projects distinctly from the face, in many animals, the nose is incorporated into the face and forms the large dorsal and lateral areas rostral to the eyes. The nostrils at the apex of the nose are the entry to the respiratory system. Once passing through the nostrils, inspired air moves through the nasal cavities and continues into the nasopharynx, larynx, trachea and lungs.
At the apical entrance to the nose the nostrils are partitioned by the nasal septum to divide the nasal cavity into right and left halves. The caudal portion of the septum is typically bony, while rostrally the septum consists of cartilage which becomes progressively more flexible toward the apex.
The wall of the nose consists of skin externally and a middle supporting layer of bone caudally and cartilage rostrally. The nasal cavity is lined by a mucous membrane. The rostral bones forming the wall of the nose include the nasal, maxillary and incisive bones. The free borders of the nasal and incisive bone provide attachment for the cartilages which support the nostrils. The supporting bones and cartilages of the nose are associated with the nasal muscles that regulate the size of the nostrils.
The dorsal and ventral lateral nasal cartilages are formed by the widening of the rostral part of the nasal septum along its dorsal and ventral margins. In the horse, the ventral lateral nasal cartilage is small and may be absent. In many domestic animals, there is no lateral support for the soft tissue over the rostral nasal passage caudal to the nostril.
A further difference in the formation of the nasal cartilages of the horse is the presence of alar cartilages. The alar cartilages consist of a ventral cornu and a dorsal lamina and support the nostrils dorsally, medially and ventrally. The lamina of the alar cartilage and the medial accessory cartilage support the nasal diverticulum, a blind pouch in the dorsal aspect of the nostril.
The muscles of the nose and upper lip act to dilate the nostrils. This is particularly noticeable during labored breathing. In the horse, these muscles are well developed and can transform the normally semilunar nostrils to become circular.
The dorsal lateral area of the rostral nasal cavity that is caudal to the alar cartilages of the horse includes a region of unsupported soft tissue which can be drawn into the nasal cavity during inspiration of air into the nasal passages. The nasal diverticulum of the horse is a part of the soft tissue structures of the horse which can be drawn into the nasal cavity. When the soft tissue is drawn in, it can narrow the nasal cavity and reduce the area for the intake of air, thus reducing the air movement into the nasal passages and ultimately to the lungs where the oxygen is transferred in the pulmonary aveoli.
The physiological effects of reduced oxygen transfer at rest and during physical exertion in horses are documented. Some experts have theorized that exercise induced pulmonary hemorrhage (EIPH) in performance horses is caused by asphyxia due to abnormal resistance of a closed or partially closed upper airway. The upper airway being defined as the region of the respiratory tract lying between the nostrils and the windpipe at the level of the first rib. Dr. Robert Cook, xe2x80x9cEIPH or AIPE? A Tufts University Researcher suggests that bleeding is not caused by EIPH, but by asphyxiaxe2x80x9d, The Equine Athlete, p. 22-23 (March/April 1997).
Devices for dilating the outer wall tissue of the nasal passages in humans are known and described in, for example, U.S. Pat. Nos. 5,476,091; 5,533,503; 5,546,929; 5,549,103; 5,553,605; 5,611,333; and 5,653,224. Devices for supporting outer tissues of the nasal passages of animals must address the unique soft tissue and mechanical characteristics of an animal nose, particularly performance animals such as horses, camels and dogs. Support devices for the nasal passages of animals are known and described in U.S. Pat. No. 5,913,873 and International Patent Publication WO 98/47451. The entire disclosure of the foregoing patent and patent application are incorporated herein by reference.
The present invention provides support devices and methods for supporting the unsupported nasal tissues of an animal. In addition to providing features which enhance the function of a support device during use, the invention also provides components to facilitate the ease and accuracy of positioning a device on an animal""s nose. The invention further provides features which address some of the needs which arise when using a support device during certain competitive events. It will be appreciated that some of the components or features of the herein disclosed devices may also be applicable for use with human nasal dilators.
Throughout the specification, guidance may be provided through lists of examples. In each instance, the recited list serves only as a representative group. It is not meant, however, that the list is exclusive.
In general, a support device according to the invention provides support to the right and left lateral vestibular walls of a domestic animal. The device can also include a surface layer, a support layer, and an engaging layer. The support devices included can also include a carrier layer to facilitate handling and positioning of the device on an animal""s nose. In some preferred embodiments, the support device is a dark color.
In alternative embodiments, the invention provides facilitation to air flow in the nasal passages of an animal by supporting the caudal apex region of the vestibular walls of the animal.
The disclosed support devices can be used on an animal that is running free in a pasture, or wearing saddlery, harnesses or other equipment that may be attached to the nose of the animal while performing physical activity.
The devices and methods of the invention are particularly advantageous for use in horses and are beneficial for use during athletic performance or for reducing the occurrence, severity or effect(s) of respiratory diseases in an adult or young animal.